Compressor for air-brakes



(No Model.) 2 Sheets-Sheet 1. D. DUNN.

GOMPRESSOR FOB. AIR'BRAKBS.

No. 473,302; Patented Apr. 19, 1892.

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No Model.) 2 sheets-sheen 2 D.` DUNN.

COMPRESSOR PoR AIR BRAKES.

No. 473,302.- Patented Apr. 19, 1892.

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. UNITED STATES PATENT OFFICE.

DENNIS DUNN, OF MAI-IANOY CITY, PENNSYLVANIA.

COMPRESSOR FOR AIR-BRAKES.

SPECIFICATION forming part of Letters Patent No. 473,302, dated April 19, 1892.

Application tiled April 17, 1891. Serial No. 389,336. (No model.)

To all whom it may concern:

Be it known that I, DENNIS DUNN, a citizen of the United States, and a resident of Mahanoy City, in the county of Schuylkill and State of Pennsylvania, have invented certain new and useful Improvements in Compressors for Air-Brakes; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to improvements in means for compressing air to be used for setting and releasing the brakes of railroad-cars.

The object of the invention is toprovide simple and efficient means whereby the momentum of the pistons on the steam-cylinders of locomotives when the steam-supply is shut oif is utilized to compress the air for actuating the brakes.

The invention consists in the novel construction and combination of parts hereinafter fully describefhand definitely pointed out in the claim. f

In the accompanying drawings, Figure 1 is a side elevation of part of a locomotive, showing my improvements applied thereto. Fig. 2 is a sectional View of the same.

In the said drawings the reference-numeral 1 indicates a locomotive-boiler, and 2 the smoke-box.

The numeral 3 designates the steam-cylin der; 4, the steam-chest; 5, the valve; 6, the steam-supply pipe; and 7 the exhaust-pipe leading to the smoke-box and provided with a stop-cock S, under control ofthe engineer, being provided with an operating-rod 9, extending into the locomotive-cab.

Connected with each end of the cylinder at the upper part are pipes 10 10, which are brought together centrally above the cylinder and connected with a pipe 12, provided with a cock 13, under the control of the engineer. The pipe 12 extends rearwardly and is connected and communicates with an air tank or receptacle 14C for containing compressed air. The pipes 10 10 near their junction with the cylinder are provided with oppositely-acting check-valves l5, which are so constructed and arranged that one is open when the other is closed. The cylinder is also provided with air pipes 16, provided with oppositelyarranged check-valves 17, which are also so constructed and arranged that while one thereof is open the other is closed. They also work oppositely to the valves 15--that is to say, when one of said valves l5 is open the valve 17 in the same end of the cylinder is closed, and vice Versa.

The operation is as follows: When going downgrade or in approaching a station, the

steam-supply is cnt off from the cylinder and v the cock 8 in the exhaust-pipe closed and cock 13 in pipe 12 opened. The piston in the cylinder, owing to the momentum of the train, will continue to reciprocate, creating a vacuum in the cylinder and causing air to enter the cylinder alternately at each end and bev In the drawings I have illustrated but one side only of thelocomotive; but the construction will be alike on both sides, as will be obvious.

Having thus described my invention, what I claim is- In an air-compressor, the combination, with a locomotive-boiler, the steam-cylinders, the steam-chest, the valve, the steam-supply pipe, and the exhaust-pipe provided with a stopcock, of the pipes connected with the cylinders, providedv with oppositely arranged check-valves, the pipe connected therewith and provided with a stop-cock, the air-tank connected with said last-mentioned pipe, and the pipes in the steam-cylinder leading to the atmosphere and provided with oppositelyarranged check-valves, substantially as described.

In testimony that I claim the foregoing as my own I have hereunto affixed my signature in presence of two witnesses.

DENNIS DUNN.

Witnesses:

THos. F. GORMAN, JOHN T. QUIN.

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